When a plurality of regenerative braking apparatuses is connected in parallel to a power supply apparatus such as an inverter apparatus, operation levels of the respective regenerative braking apparatuses are not uniform because of component tolerance or the like. Therefore, a situation in which operations concentrate only on a part of the regenerative braking apparatuses occurs. In particular, when the nonuniformity of the operations occur among such regenerative braking apparatuses, deterioration in components of the regenerative braking apparatus on which the operations concentrate progresses rapidly, leading to a fall in reliability of an entire system. Therefore, it is necessary to prevent the operations from concentrating only on a part of the regenerative braking apparatuses and secure uniformity of the operations among the regenerative braking apparatuses.
For example, Patent Document 1 described below discloses a technology for preventing, even if an error occurs in braking setting levels of respective braking apparatuses connected in parallel to an inverter apparatus, duty from concentrating on switching elements and braking resistors of specific braking apparatuses.    Patent Document 1: Japanese Patent Application Laid-open No. 10-131206